What kind of scale do you use to measure the mass?

Mass is measured by using a balance comparing a known amount of matter to an unknown amount of matter. Weight is measured on a scale. either kilograms or grams

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l